Gear finishing



'. 3, 1946. MENTLEY I 2,411,973

GEAR Fmrsnnm Filed Jan. 2, 1943 2 Sheets-Sheet 1 mmvrox.

m a. manner ATTORNEYS M. B. MENTLEY GEAR FINISHING 2 Sheets-Sheet 2Filed Jan. 2, 1943 mmvron.

' MAX BMENTLEY ATTORNEYS Patented Dec. 3, 1946 UNITED sTA'r-ssi PATENT;OFFICE GEAR r'nnsnmc Max B. Mentley, Detroit, Mich, assignor to NationalBroach & Machine Company, Detroit, Mich, a corporation of Michigan IApplication January 2, 1243, Serial No. 471,182

Claims. (oi. all-1.0)

. l The invention relates and refers more particularly tothe finishingof gears by shaving. I J

While a' shoulder gear. such as a Bear adjoining a larger gear of a gearcluster or adjoining an enlargement, has been finished by shavin with arotary gear-like cutter at crossed axes to the shoulder gear, it hasbeen impossible to satisfactorily finish inthis manner a shoulder gearwhen the neck between the gear and larger gear or the gear andenlargement is small. such as 1%" or less.

It is an objector the present invention to fin ish gears by shaving withabevel gear-like cutter to enable finishing a shoulder gear when theneck is small.

The invention has for another object to finish helical or spur gears byshaving with a bevel gear- )like cutter.

These and other objects of the invention will become apparent from thedescription,- when taken in conjunction with the drawings, in whichFigure 1-. is a front elevation of a rotary gear cutting machine forcarrying out the method embodying the invention;

Figure 2 is a diagrammatic top plan view of a cutter and shoulder geararranged in operative relation to each other; a

Figure 3 is a front elevation of another form of rotary gear cuttingmachine.

Oneform of a rotary gear cutting machine in which my method of cuttinggears may be carried out, as illustrated in Figure 1, comprises the baseI supporting the column 2 having at its upper end the forwardlyprojectingportion l.

' 4 is a head below and having a swivel mounting on the forwardlyprojecting portion to provide for angular adjustment of the hard aboutits vertical axis. The head carries the gear-like cutter .5 which isrotatable about a horizontal axis and is positively driven by suitablemeans, such as an electric motor mountedon the column. 6 is a sub-tablevertically adjustable on the column.

The sub-table may be fed toward and away from the head by the hand wheelI and also may be automatically fed toward the head by suitable means.The sub-table carries the screw 8 which is secured from axial movementand has threaded thereon the nut 9.

The construction oaths machine as thus far described, including themechanisms for driving the cutter I, for vertically adjusting thesubtable 6 through the hand wheel I, for vertically feeding thesub-table I toward the head 4, and

to the finishing of gears 2 for driving the screw 8 is all similar tothat described in the R. S. Drummond Patent No. 2,- 270,421, issuedJanuary 20, 1942.

For the purpose of finishing a shoulder gear, such as the gear Iiiadjoining the larger gear II.

when the neck between the gears is small, such as 1% or less, I havemade thegear-like cutter I in the nature of a bevel gear-like cutterhaving I conically arranged teeth provided with shallow serrations orgashes extending from the tops to the bottoms thereof. The bevel angleof the teeth is approximately between3 and I have arranged this cutterso that it meshes at crossed axes with the gear I0 and with the centerof crossed axes between the larger end and the middle of'the cutterandwith the larger end nearest the shoulder formed by the side of the 7gear H adjoining the gear i0. More specifically,

the axes ofthe cutter I5 and the gear ID are at' teeth oi the cutter.This is accomplished by.

providing the table I! which is pivotally mounted at one end through-thepivot ll on the sub-table 6 and is adapted to be angularly moved aboutthe pivot by the adjusting screw it between the subtable and table atthe end opposite the pivot. I8

is a locking plate fixedly secured to the sub-table and adjustablysecured to the table by suitable means, such as the bolt l1 and the nutl8. The table is provided in its upper face with the ways i'l extendinglongitudinally thereof and slidably engaged by the carriage to theuppervface of which the headstock. 2i and'the tailstock 22 are secured.The headstock and the tailstock are constructed in the usual manner andhave centers engageable with the ends of the shaft l2. The angle ofinclination oi the table i3 to the sub-table 8 corresponds to the bevelof the cutter I. For reciprocating the carriage 20 to relativelyreciprocate thecutter I and the gear in axially of the gear, I haveprovided the bracket 23 angularly adjustably mounted on the bracket 24,which is fixed to the carriage. The bracket 23, as shown, is pivoted at25 to the bracket 24 and is fixedly secured in its various positions ofangular adjustment by the bolt 28 and the nut 21.

3 The bracket 23 has the spaced portions 28 and 28 which are abutted bythe ends of the nut 9.

,With this construction of machine, it will be seen that the bevelgear-like cutter 5 can be placed in mesh with the shoulder gear In byvertically adjusting the sub-table 6. It will also be seen that byangularly adjusting the head l about its vertical axis the cutter 5 canbe set with its axis crossed with respect-to the axis of the shouldergear with an angularity oi approximately 2 to and with the center of thecrossed axes nearer the larger end of the cutter. It will also be seenthatby angularly adjusting the table ii, the desired angle 01' the axisor the shoulder gear to the axis of the cutter can be secured, as wellas the proper compensation for the regrinding of the cutter to secureidentical shoulder gears. It will, furthermore, be seen thatreciprocation of the carriage 20 and the shoulder gear carried by thecarriage for the different angular settings of the table can be readilyefl'ected.

In carrying out my method, it will be noted that the shoulder gear andthe gear-like bevel cutter are placed in mesh at crossed axes with thelarger end of the cutter nearest the shoulder and with the center of thecrossed axes nearer the larger end of the cutter, as illustrated inFigure 2. It will also be noted that the cutter is positively rotatedand thereby rotates the gear while in mesh and that during the rotationthe cutter and the gear are relatively reciprocated axially of the gearand the gear is automatically fed toward the cutter at the ends of thereciprocatory stroke until the desired amount of material has been cutfrom the surfaces of the teeth to thereby properly finish the teeth ofthe gear without interference by the shoulder which is formed by theface of the larger gear adjoining the face of the smaller gear.

Figure 3 illustrates another form' of rotary gear cutting machine inwhich my method of cutting gears may be carried out. The machinedifi'ers essentially from the machine of Figure 1 .in that the carriagefor the shoulder gear is horizontally reciprocable and the head carryingthe bevel gear-like cutter is inclined at an angle,

horizontal axis of rotation and adapted to be' driven in the same manneras the tool arbor of Figure 1 of the above mentioned Drummond patent. 32is the head depending from and having a. swivel mounting on the adapter33 which, in'turn, depends from and is secured to the forwardlyprojecting portion 34 at the upper end of the column 85. 38 is the bevelgearlike cutter on the arbor, which latter naled in the head.

The machine operates in the same manner as the machine of Figure 1, withthe exception that the shoulder gear is positively rotated and in turnrotates the bevel gear-like cutter in mesh with the shoulder gear.

is jour- While it is preferable to have the gears and the cuttersarranged at crossed axes, the above machines may be used to finisheither external or internal gears of shoulder or open type with theiraxes parallel to theiaxes oi the cutters. Also, if the machines are usedto finish open external gears, a crossed axes setting of approximately 3to 30 may be employed.

What I claim as my invention is:

l. The method of finishing a shoulder gear which comprises meshing atcrossed axes the gear solely with a bevel gear-like cutter having itslarger end nearest the shoulder, rotating the gearand cutter while inmesh and during the rotation relatively reciprocating the gear andcutter axially oi the gear.

' 2. The method 01' finishing a shoulder gear .larger end nearest theshoulder, rotating one of the members and thereby rotating the other ofthe members and relatively reciprocating the members during rotation.

3. The method of finishing a shoulder gear which comprises meshing thegear solely with a bevel gear-like cutter having its larger end nearestthe shoulder and with the axes of. the gear and cutter inclined withrespect to each other in transverse planes, rotating the gear and cutterwhile in mesh, relat vely reciprocating the gear and cutter axially othe gear during the rotation, and relatively feeding the gear and cuttertoward each other during the relative reciprocat'ion.

4. The method of shaving a shouldered gear which consists in meshingwith such a gear a tapered shaving cutter of which the teeth are soarranged with relation to' the teeth of the gear that, when the cutteris placed in correct mesh with the gear the cutter is inclined away fromthe shoulder of the gear and its axis is in crossed relation to the axisof the gear, and running the cutter and gear in mesh together.

5. The method of shaving a shouldered gear which consists in placing aconjugate tapered shaving tool in mesh with the gear with its larger endadjacent to-the gear shoulder and its plane both inclined from themeshing point away from the gear shoulder and oblique to the plane ofrotation oi. the gear at such an angle as to cause relative lengthwiseslip between the mating rotation of the gear at such an angle as tocause relative lengthwise slip between the mating teeth in consequenceof their simultaneous rotation, rotating'the cutter and gear in meshwith pressure contact between their mating teeth.

and effecting a relative reciprocation between the cutter and gear inthe direction of the axis oi the gear.

